The present invention is directed to an improved storage system for use with computing devices, especially differential sense amplifiers. Differential amplifiers are widely used in memory sensing circuitry accessing. In particular, the present invention is directed to a storage system using a differential sense amplifier for accessing information within a memory array in the system, the storage system having improved stability in its response in the presence of varying ambient conditions, such as temperature and manufacturing variations of components.
In computer storage systems much design effort has been expended in optimizing tracking between the bit line to be sensed in a memory array and a dummy bit line providing a reference voltage to a differential sense amplifier. Elaborate techniques, such as dummy flash cells or the like, have been employed to establish a dummy bit line providing a stable reference voltage between the logical "0" signal level and the logical "1" signal level of a digital circuit in which the differential amplifier and its associated memory array are employed. Various devices have been employed to mimic a true cell as a dummy reference cell supplying a dummy bit line in a differential memory sensing circuit. However, ambient conditions and electrical conditions affect the dummy cell components and the memory array differently; the dummy bit line, and the bit line to be measured in comparison to the dummy bit line to indicate the contents of the memory array, do not respond to those conditions equally. Inaccurate indications of the contents of the memory array may result.